FIELD OF THE INVENTION
The invention relates to a pressure sensor component having a chip carrier with a substantially planar chip carrier surface and a semiconductor chip on the chip carrier surface. The semiconductor chip has an integrated a pressure sensor with a pressure-detecting area exposed to the pressure to be measured. The device has a component encapsulation made of an electrically insulating material enclosing the semiconductor chip and/or the chip carrier at least in regions. The invention furthermore relates to a method for producing such a pressure sensor component.
In order to measure pressures, the medium to be measured must be brought up to the sensor, or the pressure prevailing in the medium must be transmitted to the sensor. On the other hand, the application of a semiconductor pressure sensor in the final use requires that the sensor chip be provided with a protective encapsulation by being covered with a suitable material, normally plastic. What is known in this case is the application of the semiconductor chip, usually resting on silicon as the base material, in a housing, for example DIP housing (Dual Inline Package housing), SMD housing (Surface Mounted Design housing), or else in special designs, the housing subsequently being mounted on a printed circuit board.
In one prior art embodiment, the pressure coupling is effected by means of a diaphragm which covers and thus protects the sensitive sensor, is made of metal or else plastic and can also be embodied as a separate additional structural part. Problems frequently arise in that case because pressure is coupled in only insufficiently through the housing as far as the sensor chip with the sensor simultaneously being protected. What is required, in general, is a tight connection between the medium to be measured and the sensor, which connection is simple to produce, in order to avoid extraneous air flowing in which could falsify the pressure measurement. On the other hand, in many cases there is, moreover, a requirement to separate the medium to be measured from the metallic constituents of the sensor and also from the semiconductor chip, in order to avoid the risk of corrosion or destructive influence by the medium on the sensitive constituents of the sensor. Other embodiments of known pressure sensor components provide an open housing in which the protection of the sensor chip against environmental influences is regarded only as a problem of secondary importance, and the sensor chip is not protected. Such designs are generally suitable only for non-aggressive media.
European published patent application EP 0 436 158 A2 describes a solid-state pressure sensor comprising a pressure space which is open toward two opposite sides and also comprises a distortion sensor element formed by a silicon diaphragm. Each partial space of the pressure space thereby forms a hermetically sealed, separate space with the connection. The arrangement is furthermore encapsulated by a housing which, with O-rings, seals the connection flanges penetrating through the housing. The measurement principle is in this case based on the flexure of the silicon diaphragm which is picked up by sensor elements applied on the diaphragm.
European published patent application EP A 0 690 297 A1 describes a housing for electronic components and the production thereof, in which a pressure inlet opening is formed in the upper region of the encapsulation housing. The opening forms a connection piece in a chimney-shaped manner and is designed to be integral with the encapsulation housing. U.S. Pat. No. 4,680,569 describes a semiconductor pressure sensor with a semiconductor diaphragm chip whose pressure-detecting area is connected in a pressure-tight manner to the housing exterior via chimney-shaped connection penetrating through the housing.
It is common to all the previously known configurations of semiconductor pressure sensors that their production always necessitates a multistage process for covering or encapsulating the component, by means of which process the component is brought to its desired design.